Gas analyzer

Abstract

A gas analyzer includes an optical emitter that irradiates measurement light into a measurement region including a gas to be measured; a reflector that reflects the measurement light irradiated from the optical emitter; an optical receiver that receives the measurement light reflected by the reflector; and an aligner that expands a beam diameter of the measurement light at the reflector.

The invention claimed is: 
     
       1. A gas analyzer comprising:
 an optical emitter that irradiates measurement light into a measurement region including a gas to be measured; 
 a probe that extends along an optical axis of the measurement light so as to overlap the measurement region inside the probe; 
 a reflector that reflects the measurement light irradiated from the optical emitter and that is positioned at an opposite side of the probe from the optical emitter; 
 an optical receiver that receives the measurement light reflected by the reflector; and 
 an aligner that expands a beam diameter of the measurement light at the reflector to a value at which the measurement light includes the reflector, wherein the value is based on a length of the probe and an amount of the measurement light that the optical receiver needs to receive for analysis of the measurement light. 
 
     
     
       2. The gas analyzer of  claim 1 , wherein the aligner expands the beam diameter of the measurement light to be greater than a width of the reflector in a direction substantially orthogonal to an optical axis of the measurement light. 
     
     
       3. The gas analyzer of  claim 1 , wherein the aligner comprises an optical lens disposed between the optical emitter and the measurement region and that condenses the measurement light. 
     
     
       4. The gas analyzer of  claim 3 ,
 wherein the optical lens is a plano-convex lens, 
 wherein a flat surface of the plano-convex lens faces the optical emitter, and 
 wherein a convex surface of the plano-convex lens faces the measurement region. 
 
     
     
       5. The gas analyzer of  claim 3 , wherein the aligner further comprises an alignment mechanism that changes a distance between the optical lens and the optical emitter along an optical axis of the measurement light. 
     
     
       6. The gas analyzer of  claim 5 ,
 wherein the alignment mechanism comprises an alignment screw rotatably supported about an axis substantially parallel to the optical axis by a fastener that fixes the optical lens, and 
 wherein one end of the alignment screw is in contact with the optical emitter, and another end of the alignment screw is exposed from the fastener at an opposite side from the optical emitter.